Oddveig Rikardsen

The Role of Reactive Oxygen Species in Integrin and Matrix Metalloproteinase Expression and Function

Cell adhesion and migration is largely dependent on integrin binding to extracellular matrix, and several signalling pathways involved in these processes have been shown to be modified by reactive oxygen species (ROS). In fact, integrin activation is linked to increased ROS production by NADPH-oxidases, 5-lipoxygenase, and release from mitochondria. Cell migration is intimately linked to degradation of the extracellular matrix, and activated matrix metalloproteinases (MMPs) are a prerequisite for cancer cell invasion and metastasis. In this minireview, we focus on the interplay between integrin-mediated ROS production and MMP expression as well as its biological and pathobiological significance.

Urokinase Plasminogen Activator Receptor (uPAR) and Plasminogen Activator Inhibitor-1 (PAI-1) Are Potential Predictive Biomarkers in Early Stage Oral Squamous Cell Carcinomas (OSCC)

Oral squamous cell carcinoma (OSCC) is often associated with metastatic disease and a poor 5 year survival rate. Patients diagnosed with small tumours generally have a more favourable outcome, but some of these small tumours are aggressive and lead to early death. To avoid harmful overtreatment of patients with favourable prognosis, there is a need for predictive biomarkers that can be used for treatment stratification. In this study we assessed the possibility to use components of the plasminogen activator (PA) system as prognostic markers for OSCC outcome and compared this to the commonly used biomarker Ki-67. A tissue-micro-array (TMA) based immunohistochemical analysis of primary tumour tissue obtained from a North Norwegian cohort of 115 patients diagnosed with OSCC was conducted. The expression of the biomarkers was compared with clinicopathological variables and disease specific death. The statistical analyses revealed that low expression of uPAR (p = 0.031) and PAI-1 (p = 0.021) in the tumour cells was significantly associated with low disease specific death in patients with small tumours and no lymph node metastasis (T1N0). The commonly used biomarker, Ki-67, was not associated with disease specific death in any of the groups of patients analysed. The conclusion is that uPAR and PAI-1 are potential predictive biomarkers in early stage tumours and that this warrants further studies on a larger cohort of patients.

Stromal impact on tumor growth and lymphangiogenesis in human carcinoma xenografts

Squamous cell carcinomas (SCCs) arising in the oral cavity are associated with poor survival, mainly due to metastatic disease. In contrast, skin SCCs rarely metastasize and are usually curable. To study influence of tongue and skin stroma on cancer growth and induction of lymphangiogenesis, xenograft tumors of human carcinoma cells were established either in tongue or skin of BALB/c nude mice. Two oral and two skin SCC cell lines were used, as well as an endometrial adenocarcinoma cell line. Tongue tumors established from all cell lines were larger than corresponding skin tumors. Peritumoral lymphatic vessel density was up to five times higher in tongue than in corresponding skin tumors, and mRNA level of the lymphangiogenic growth factor vascular endothelial growth factor (VEGF)-C was twice as high in tongue tumors compared with corresponding skin tumors. Contrary to lymphatic vessel density, blood vessel density was higher in skin tumors than in tongue tumors. In a cohort of patient samples, lymphatic vessel density was found to be higher in tongue SCCs compared with skin SCCs, supporting a clinical relevance of our findings. Our results show that the tumor stroma has a profound impact on cancer growth and induction of lymphangiogenesis and angiogenesis. The difference in lymphatic vessel density between tongue and skin tumors may be important in directing metastatic potential of tumors arising in these organs.

Organ specific regulation of tumour invasiveness and gelatinolytic activity at the invasive front

Proteolytic enzymes play a complex role in tumour growth and invasion. To explore the impact of tumour stroma on invasiveness and expression of proteolytic enzymes, we used a xenograft mouse model where tumours in tongue and skin were established from various human cancer cell lines. Gelatinolytic activity in the tumours was investigated by a novel in situ zymography technique which enables high image resolution. In vivo and in vitro expression of various proteolytic enzymes were analysed at transcriptional and protein level using RT-qPCR, immunohistochemistry and SDS-PAGE substrate zymography. At the mRNA level all cell lines were found to express MMP-2, -7, -14, uPA and uPAR. In addition, two out of three cell lines expressed MMP-9. Histological analyses revealed that tongue tumours had an invasive growth pattern, associated with reduced E-cadherin expression. In contrast, the skin tumours established from the same cell lines were non-invasive. Tongue tumours of all cell lines showed strong gelatinolytic activity especially at the invasive front, which was not seen in the non-invasive skin tumours. Our results show a close relationship between tumour invasiveness and gelatinolytic activity at the tumour front. Furthermore, in our model, both invasiveness and activity of tumour-associated proteolytic enzymes were more dependent on the tumour microenvironment than on inherent properties of the cancer cells.

Radiological imaging of the neck for initial decision-making in oral squamous cell carcinomas-A questionnaire survey in the Nordic countries

Background. Fast and accurate work-up is crucial to ensure the best possible treatment and prognosis for patients with head and neck cancer. The presence or absence of neck lymph node metastases is important for the prognosis and the choice of treatment. Clinical lymph node (N)-staging is done by palpation and diagnostic imaging of the neck. We investigated the current practice of the initial radiological work-up of patients with oral squamous cell carcinomas (OSCC) in the Nordic countries. Methods. A questionnaire regarding the availability and use of guidelines and imaging modalities for radiological N-staging in OSCC was distributed to 21 Head and Neck centres in Denmark (n = 4), Finland (n = 5), Iceland (n = 1), Norway (n = 4) and Sweden (n = 7). We also asked for a description of the radiological criteria for determining the lymph nodes as clinical positive (cN+) or negative (cN0). Results. All 21 Head and Neck centres responded to the questionnaire. Denmark and Finland have national guidelines, while Norway and Sweden have local or regional guidelines. Seventeen of the 19 centres with available guidelines recommended computed tomography (CT) of the cN0 neck. The waiting time may influence the imaging modalities used. Lymph node size was the most commonly used criteria for radiological cN+, but the cut-off measures vary from 0.8 to 2.0 cm. Conclusion. Overall, CT is the most commonly recommended and used imaging modality for OSCC. Despite availability of national guidelines the type and number of radiological examinations vary between centres within a country, but the implementation of a fast-track programme may facilitate fast access to imaging. The absence of uniform criteria for determining the lymph nodes of the neck as cN+ complicates the comparison of the accuracy of the imaging modalities. Well-defined radiological strategies and criteria are needed to optimise the radiological work-up in OSCC.

S100A4 Expression in Xenograft Tumors of Human Carcinoma Cell Lines Is Induced by the Tumor Microenvironment

Increased expression of the invasion- and metastasis-associated protein S100A4 is found in many types of cancer, but the regulation of S100A4 expression is poorly understood. The microenvironment surrounding tumors has a significant effect on tumor progression, and in the present study, we investigated the role of the microenvironment in the expression of S100A4. Tumors of three different human carcinoma cell lines were established in the tongue or skin of mice, and S100A4 expression was assessed by quantitative RT-PCR, Western blotting, and immunohistochemical analysis in tumors and stromal tissue and in cancer cells grown in vitro. Tongue tumors of the oral squamous cell carcinoma cell line HSC-4 showed a pronounced increase in S100A4 expression during tumor growth, whereas only a minor increase was detected in skin tumors of the same cell line. The S100A4 expression correlated with the methylation status of cytosine-guanine sites in the first intron of the gene. For all cell lines, S100A4 expression in the tumor stroma was related to the presence of inflammatory cells rather than to the level of S100A4 in the tumor cells.

Presence of tumour high-endothelial venules is an independent positive prognostic factor and stratifies patients with advanced-stage oral squamous cell carcinoma

Staging of oral squamous cell carcinoma is based on the tumour-node-metastasis (TNM) system, which has been deemed insufficient for prognostic purposes. Hence, better prognostic tools are needed to reflect the biological diversity of these cancers. Previously, high numbers of specialized blood vessels called high-endothelial venules have been reported to be associated with prolonged survival in patients with breast cancer. In this study, we analysed the prognostic value and morphological characteristics of tumour-associated high-endothelial venules in oral cancer. The presence of tumour-associated high-endothelial venules was evaluated by immunohistochemistry in 75 patients with oral squamous cell carcinoma and analysed with correlation to clinicopathological parameters, patients’ survival and vessel morphology. Ten of the samples were analysed at multiple levels to evaluate intratumoural heterogeneity. The presence of tumour-associated high-endothelial venules was found to be associated with lower disease-specific death in multivariate regression analyses (P = 0.002). High-endothelial venules were present in all (n = 53) T1-T2 tumours, but only in two thirds (n = 14) of the T3-T4 tumours. The morphology of high-endothelial venules was heterogeneous and correlated with lymphocyte density. High-endothelial venules were found to be distributed homogeneously within the tumours. We found the presence of tumour-associated high-endothelial venules to be an easy-to-use, robust, and independent positive prognostic factor for patients with oral cancer. Absence of these vessels in advanced-stage tumours might identify patients with more aggressive disease. Evaluating the presence of tumour-associated high-endothelial venules might help to tailor the treatment of oral cancer patients to their individual needs.

Transoral Robotic Surgery in the Nordic Countries: Current Status and Perspectives

Background: The five Nordic countries with a population of 27 M people form a rather homogenous region in terms of health care. The management of head and neck cancer is centralized to the 21 university hospitals in these countries. Our aim was to gain an overview of the volume and role of transoral robotic surgery (TORS) and to evaluate the need to centralize it in this area as the field is rapidly developing. Materials and Methods: A structured questionnaire was sent to all 10 Departments of Otorhinolaryngology—Head and Neck Surgery in the Nordic countries having an active programme for TORS in December 2017. Results: The total cumulative number of performed robotic surgeries at these 10 Nordic centers was 528 and varied between 5 and 240 per center. The median annual number of robotic surgeries was 38 (range, 5–60). The observed number of annually operated cases remained fairly low (<25) at most of the centers. Conclusions: The present results showing a limited volume of performed surgeries call for considerations to further centralize TORS in the Nordic countries.

Abstract 543: Stromal impact on tumor invasiveness and gelatinolytic activity at the invasive front

The aim of this study was to explore the impact of tumor stroma on invasiveness and expression of gelatinases in xenograft carcinomas. Xenograft tumors of various human carcinoma cells were established either in the tongue or the skin of BALB/c Nude mice. Cell lines originating from oral and skin SCCs were used, as well as a cell line foreign to both organs. Gelatinolytic activity in the tumors was investigated by a novel in situ zymography technique which enables high image resolution. In vivo and in vitro expression of various proteolytic enzymes were analyzed at transcriptional and protein level using RT-qPCR, immunohistochemistry, Western blotting and SDS-PAGE substrate zymography. Tongue tumors showed an invasive growth pattern, whereas the skin tumors established from the same cell lines were non-invasive. Although the repertoire of proteolytic enzymes differed between the cell lines, the tongue tumors of all cell lines showed strong gelatinolytic activity, especially at the invasive front. In contrast, the skin tumors showed only weak gelatinolytic activity. Our results suggest that invasiveness as well as activity of proteolytic enzymes in the tumors is more dependent on the tumor microenvironment than on inherent properties of the cancer cells. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 543.